High power optical beams, such as those produced by lasers, are used for applications such as long range laser detection and ranging (“LADAR”), directed energy weapons, or other high power laser applications. High power lasers typically have optical output beams with over 1 kilowatt (kW) of power, and can have optical output beam powers that reach the hundreds of kilowatts or even megawatts. One difficulty in creating laser beams of very high powers is that beam quality typically degrades as laser power levels are increased. This degradation with increasing power is frequently a consequence of thermally induced distortions. Poor beam quality causes the laser area at a target to be larger than a non-distorted beam. Efforts have been made to combine the outputs from multiple lower power lasers into a single high power beam to achieve both high power and minimize degradation of beam quality.
Beam control remains one of the most significant challenges for deployment of high power laser systems for LADAR, directed energy weapons, or other high laser power applications. Typically, beam-steering and control has been achieved by the use of bulky, mechanical gimbal beam directors. For example, the airborne laser (“ABL”) turret and the ground-based high energy laser system terrestrial facility (“HELSTF”) beam directors have traditionally relied on such mechanical gimbal beam directors. These beam control systems are separate from the high power laser itself, thus adding considerable size, weight, and power considerations to already unwieldy systems that are challenging to deploy. In addition, because of their large size, traditional mechanical beam directors do not have as fast a response as desired, particularly for applications such as LADAR, ABL and HELSTF. Although electronic beam steering techniques have recently been developed, such techniques are presently limited by low damage thresholds of components and very low throughput. Thus, such techniques are unsuitable for high power systems.